Butterfly valve

ABSTRACT

A butterfly valve includes a valve housing ( 1 ) having a substantially cylindrical flow passage formed therein, a disc-shaped valve element ( 4 ) arranged in the flow passage so as to be rotatable therein, a stem ( 3 ) extending from the valve element ( 4 ) to its outside and supported by the valve housing ( 1 ) so as to be rotatable, and an operating unit ( 8 ) for rotating the stem ( 3 ). The rotation of the stem ( 3 ) rotates the valve element ( 4 ) in the flow passage to open and close the flow passage. A top flange ( 2 ) for mounting the operating unit ( 8 ) is formed integrally with the valve housing ( 1 ). The top flange is formed with a plurality of cutouts ( 12 ) extending from the outer peripheral edge of the top flange toward the center thereof.

TECHNICAL FIELD

The present invention relates to a butterfly valve used for a fluidtransportation pipe line in various industries and, more particularly,to a butterfly valve which can be used at an end of a pipe and which hasa structure that can be easily switched from manual to automatic mode orfrom automatic to manual mode, using the same valve housing, while beingarranged in the pipe line.

BACKGROUND ART

Generally, the on-off operation of the butterfly valve is performed ineither manual or automatic mode by an operating unit connected to a stemof the butterfly valve. The operating unit includes a lever-typeoperating unit, a gear-type operating unit, an actuator, etc., of whichthe size and the pitch circle diameter of the mounting bolts are notuniform. Therefore, in the case where the mounting dimensions of theoperating unit are different from those of the top flange of thebutterfly valve, a valve housing having a top flange suitable for eachoperating unit has been prepared for a different purpose, or the topflange has been post-processed or a dedicated intermediate flange orjoint has been used.

U.S. Pat. No. 5,564,461 proposes a butterfly valve shown in FIG. 7 as anexample of a solution to this problem. In this butterfly valve, anintermediate flange 39 having cutouts 38 formed therein is interposedbetween a valve housing 36 and an automatic operating unit 37. Thecutouts 38 of the intermediate flange 39 each engage a correspondingsegment 43 having a male screw 41 and female screw 42 formed therein tofix the top flange 40 on the automatic operating unit 37. In theconnecting process, the intermediate flange 39 is engaged with thesegments 43 screwed on the automatic operating unit 37, and the segment43 is screwed by several connecting bolts 44 with the intermediateflange 39 interposed between the top flange 40 and the automaticoperating unit 37. Thus, a plurality of types of operating units havingdifferent mounting dimensions can be connected to the valve housing 36by changing the male screws 41 and female screws 42 of the segments 43.

Japanese Examined Utility Model Publication No. 4-24218 proposes abutterfly valve shown in FIG. 8. In this butterfly valve, anintermediate flange 47 is interposed between a valve housing 45 and anautomatic operating unit 46. The intermediate flange 47 is formed withholes through which mounting bolts 48 for fixing the automatic operatingunit 46 and the intermediate flange 47 to each other are inserted andholes through which connecting bolts 50 for fixing the intermediateflange 47 and the top flange 49 to each other are inserted. In theconnecting process, the mounting bolts 48 inserted through theintermediate flange 47 are fastened to the automatic operating unit 46and the connecting bolts 50 inserted through the intermediate flange 47are fastened to the valve housing 45 thereby to connect the automaticoperating unit 46 and the valve housing 45 to each other. As a result,any of a plurality of types of the valve housing 45 and the operatingunit can be combined with each other using a single intermediate flange47.

The use of the butterfly valve having the structure described aboveeliminates the need of preparing a plurality of valve housings eachhaving a top flange adapted for each driving unit to use any one of themfor different purposes, post-processing the top flange or using adedicated intermediate flange or joint, even if the mounting dimensionsof the operating unit are different from those of the top flange of thebutterfly valve. However, the conventional butterfly valve still hasproblems described below.

Firstly, the use of such a part as an intermediate flange or a jointincreases the production cost as well as the product dimensions anddeteriorates the production efficiency. Further, in the case where ajoint is used, the operating unit and the stem may be displacedoff-center from each other or a fitting failure may occur between thejoint, the operating unit and the stem.

Secondly, in the case where a replacement space for mounting anddemounting the operating unit is limited by the pipe flanges holding thebutterfly valve when the butterfly valve placed in the pipe line ischanged from manual to automatic mode or from automatic to manual mode,the bolts fixing the top flange and the operating unit are difficult toremove. Therefore, the butterfly valve is required to be removed fromthe pipe line.

Thirdly, when fixing the operating unit by inserting the bolts throughthe bolt holes formed in the top flange, the length of the housing neckand the stem supporting the valve housing and the top flange is requiredto be increased in order to avoid interference between the bolts and thelugs of the valve housing, thereby increasing the production cost.Further, the increased length of the housing neck concentrates thestress on the housing neck when mounting the heavy operating unit on thebutterfly valve, and the strength of the valve housing may be affected.Also, the increased length of the stem increases the deflection of thestem when pressure is imparted to the valve element by the watersupplied to the butterfly valve mounted in the pipe line, therebyprobably affecting the stem strength. Further, the effect on the housingneck and the stem causes the deformation of the valve housing, etc.,thereby decreasing the sealing performance and increasing the torque forthe valve on-off operation. This is noticeable especially in the casewhere the valve is used so that only one side thereof is connected tothe pipe or it is arranged at an end of the pipeline.

DISCLOSURE OF THE INVENTION

The object of the present invention is to solve the above-mentionedproblems of the prior art and to provide a butterfly valve having astructure in which a sealing performance is high and which uses the samevalve housing to facilitate the switching from manual to automatic modeor automatic to manual mode.

According to the present invention, in order to achieve theabove-mentioned object, there is provided a butterfly valve comprising avalve housing having a substantially cylindrical flow passage formedtherein, a disc-shaped valve element arranged in the flow passage so asto be rotatable therein, a stem extending from the valve element to theoutside of the valve housing and supported by the valve housing so as tobe rotatable, and an operating unit for rotating the stem, the butterflyvalve adapted so that flow passage is opened and closed by rotating thestem to thereby rotate the valve element in the flow passage, whereinsaid butterfly valve further comprising a top flange for mounting theoperating unit thereon which is formed integrally with the valvehousing, the top flange formed with a plurality of cutouts extendingfrom the outer peripheral edge of the top flange toward the centerthereof.

Preferably, the above butterfly valve further comprises an annular seatring extending in a circumferential direction of the flow passage andfitted between the inner peripheral surface of the flow passage and theouter peripheral edge of the valve element, wherein the stem extendsthrough the seat ring, the seat ring including a body and flanges formedat both axial ends of the body, the seat ring formed so that the outerperiphery of the body thereof has an ellipse shape having a long axisextending along an axis of the stem and so that inner periphery of thebody thereof has a circular shape.

More preferably, a groove for a spacer for preventing the stem fromcoming off to be fitted therein is formed on the upper surface of thetop flange.

In the butterfly valve according to the present invention, a pluralityof cutouts extending from the outer peripheral edge of the top flangetoward the center thereof is formed on the top flange for mounting theoperating unit thereon. Therefore, the pitch circle diameter of theconnecting bolts for connecting the operating unit and the top flange toeach other can be changed to the corresponding various pitch circlediameters. Further, the connecting bolts can be inserted into thecutouts from the outer peripheral edge of the top flange. Therefore,even if a space between the valve housing and the top flange is limited,the connecting bolts can be easily removed and the operating unit can bemounted and demounted easily.

Also, as the top flange is formed integrally with the valve housing,such parts as an intermediate flange or a joint separate from the valvehousing are not required, and the off-center arrangement between theoperating unit and the stem hardly occurs.

If a flange is formed on the body of the annular seat ring arrangedbetween the inner peripheral surface of the flow passage and the outerperipheral edge of the valve element, the seat ring can be preventedfrom moving in the flow passage. Further, if the seat ring is formed sothat the outer periphery of the body thereof has an elliptical shapehaving a long axis extending along an axis of the stem and so that theinner periphery of the body thereof has a circular shape, the innerperiphery of the seat ring is in an elliptical shape when the seat ringis mounted on the inner peripheral surface of the substantiallycylindrical flow passage. Thus, the sealing performance between theinner peripheral surface of the seat ring and the outer peripheral edgeof the valve element is improved at the portion of the inner peripheryof the seat ring through which the stem passes.

Also, if a spacer is mounted on the upper surface of the top flange, thestem is prevented from coming off when the operating unit is removed.Therefore, the operating unit can be changed safely.

The material of the valve according to the present invention may be aplastic such as polyvinyl chloride, polypropylene or polyvinylidenefluoride, or a metal, and is not especially limited.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will be made apparent from the following detailed descriptionof embodiments of the invention taken with reference to the accompanyingdrawings, in which:

FIG. 1 is a longitudinal sectional view of a butterfly valve having alever-type operating unit mounted thereon according to the presentinvention;

FIG. 2 is a plan view of the butterfly valve of FIG. 1 with thelever-type operating unit removed;

FIG. 3 is a front view of the butterfly valve of FIG. 2 having agear-type operating unit mounted thereon;

FIG. 4 is a front view of the butterfly valve of FIG. 2 having anautomatic operating unit mounted thereon;

FIG. 5 is a longitudinal sectional view of a seat ring for use with thebutterfly valve according to the present invention;

FIG. 6 is a partly cutaway perspective view of the seat ring for usewith the butterfly valve according to the present invention;

FIG. 7 is an exploded perspective view showing a conventional butterflyvalve connected with an operating unit; and

FIG. 8 is a front view showing a conventional butterfly valve connectedwith an operating unit.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described below, withreference to the drawings, but the present invention is, of course, notlimited to these embodiments.

Referring to FIGS. 1 and 2, a butterfly valve includes a valve housing1, a stem 3, a valve element 4, a seat ring 5, a spacer 6 for preventingthe stem from coming off, and a locking plate 7.

The valve housing 1 is made of resin and, preferably, of polyvinylchloride, polypropylene or polyvinylidene fluoride which are high inchemical resistance. A substantially cylindrical flow passage is formedin the valve housing 1, and a plurality of lugs 9 each formed with abolt insertion hole for a piping bolt to be screwed are projected fromthe outer periphery of the valve housing 1. A thick flange-like baseplate 10 is formed in the neighborhood of the cental portion of theouter periphery of the valve housing.

The top flange 2 has a disc-like shape and is formed integrally with theupper part of the neck 11 of the valve housing 1. A lever-type operatingunit 8, a gear-type operating unit 16 (FIG. 3) or an automatic operatingunit 18 (FIG. 4) is mounted on the top flange 2. The top flange 2 isformed with four cutouts 12 equidistantly around the center of the topflange 2 for fixing the gear-type operating unit 16 or the automaticoperating unit 18 by connecting bolts 17 (FIG. 3).

These cutouts 12 are formed through from the upper end to the lower endof the top flange 2 to extend from the outer peripheral edge of the topflange 2 toward the center thereof. The inner end of each cutout 12 isterminated before reaching the stem through hole 13. Further, a groove14 for fitting therein the spacer 6 for preventing the stem from comingoff and a groove 15 for fitting therein the locking plate 7 required formounting the lever-type operating unit 8 are formed at the central partof the upper surface of the top flange 2 so as to be different in level.

The stem 3 is made of SUS, and includes a stem body 19, and areduced-diameter stem portion 20 located on the top of the stem body 19and having a smaller outer diameter than the stem body 19. The upper endof the reduced-diameter stem portion 20 is arranged to be projected fromthe center of the top flange 2 provided at the upper portion of thevalve housing 1, and is fixed on the lever-type operating unit 8 bybolts (not shown) with the upper end thereof extending through thethrough-hole 32 of the spacer 6 and through the through-hole 34 of thelocking plate 7. The central portion of the stem 3 extends closelythrough the valve housing 1 and the seat ring 5 so as to be rotatabletherein.

The valve element 4 is made of resin and has a disc-like shape. Thevalve element 4 is arranged at the central portion in the valve housing1, and is fixedly mounted on the stem 3 rotatably extending through thecentral portion of the valve housing 1. Therefore, the valve element 4rotates along with the rotation of the stem 3 in the seat ring 5 fittedin the valve housing 1, so that the outer peripheral edge of the valveelement 4 is pressed against or separated from the inner periphery 27 ofthe seat ring 5 thereby to open and close the valve.

The seat ring 5 is made of elastomer or other elastic material and, asshown in FIGS. 5 and 6, includes a hollow cylindrical body 21, andflanges 22 integrally formed at both axial ends of the body 21. Thecylindrical body 21 has a pair of stem through-holes 23 in diametricallyopposed relation to each other for the stem 3 extending therethrough.The outer periphery 24 of the body 21 is formed in an elliptical shapehaving a long axis extending along a line connecting the two stemthrough-holes 23. In other words, the outer periphery 24 of the body 21is formed so as to have the largest thickness along vertical directionconnecting the two stem through-holes 23 and the smallest thicknessalong the horizontal direction orthogonal to the vertical direction.

The axial central portion of the outer periphery 24 of the seat ring 5is formed with an annular protrusion 25 having a rectangular section.This annular protrusion 25 is fitted in the fitting groove formed on theinner peripheral surface of the valve housing 1 to prevent the axialmovement of the seat ring 5. A ring 26 made of SUS is fitted on theperipheral surface of each stem through-hole 23 of the body 21. Theinner periphery 27 of the seat ring 5, which the valve element 4 ispressed against or separated from, is formed so as to have a planecylindrical surface. Further, the peripheral edge of each stemthrough-hole 23 is formed with a boss 28 having a spherical surfaceconforming to the shape of the valve element 4 to thereby improve thesealing performance of the valve seat. The outer periphery 29 of theflange 22 formed integrally with each axial end of the seat ring 5 isformed in a circular shape, and the lug 30 projecting inward from theouter end of each flange 22 is fitted on the outer peripheral surface ofthe valve housing 1 to prevent the movement of the seat ring 5.

The inner periphery of the opening 31 formed at the central portion ofthe valve housing 1 has a circular shape, while the outer periphery 24of the seat ring 5 has an elliptical shape. Therefore, when the seatring 5 is fitted in the valve housing 1, the flow passage defined by theinner periphery 27 of the seat ring 5 has an elliptical shape having ashort axis extending in a direction along the stem axis connecting thestem through-holes 23. As a result, the inner periphery 27 of the seatring 5 and the outer peripheral edge of the valve element 4 contact eachother more closely near the stem through-holes 23 of the seat ring 5than at the remaining portion, thereby making it difficult to developleakage from the valve seat through the stem through-holes 23. On theother hand, in the portion other than near each stem through-hole 23,the proper sealing performance is maintained between the inner periphery27 of the seat ring 5 and the outer peripheral edge of the valve element4 and, therefore, the operating torque is not unnecessarily increased.

The spacer 6 for preventing the stem for coming off is made of resin andhas a substantially disc-like shape. The central portion of the spacer 6is formed with a circular through-hole 32 larger than the outer diameterof the reduced-diameter stem portion 20 and smaller than the outerdiameter of the stem body 19. Four securing holes 33 are formed along aconcentric circle around the through-hole 32 for securing the spacer 6in the groove 14 of the top flange 2. The spacer 6 is inserted aroundthe upper end of the reduced-diameter stem portion 20 projecting fromthe central portion of the top flange 2 so as to be rotatable, and isfixed by fastening means such as screws in the groove 14 formed at theupper end of the top flange 2 so that the spacer 6 presses the upper endsurface of the stem body 19 downward.

The locking plate 7 is made of resin and has a generally disc-likeshape. A circular through-hole 34 is formed at the central portion ofthe locking plate 7, and four fixing holes (not shown) are formed alonga concentric circle around the through-hole 34 for fixing the lockingplate 7 to the top flange 2. Also, a part of the outer peripheral edgeof the locking plate 7 is provided with a stopper (not shown) foradjusting the opening degree of the valve. The locking plate 7 is fixedon the top flange 2 by passing the reduced-diameter stem portion 20through the through-hole 34 with the spacer 6 held between the topflange 2 and the locking plate 7, inserting the screws through thefixing holes of the locking plate 7 and engaging the screws in the screwholes 35 of the groove 15 for fixing the locking plate 7.

Next, the operation of this embodiment of the valve will be described.

When the lever-type operating unit 8 in is rotated by 90 degrees fromthe fully closed state of the butterfly valve shown in FIG. 1, the stem3 and the valve element 4 also rotate accordingly to thereby fully openthe butterfly valve. When the lever-type operating unit 8 is rotated by90 degrees in the reverse direction from the fully opened state of thevalve, the outer peripheral edge of the valve element 4 is pressedagainst the inner peripheral surface 27 of the seat ring 5 to therebyfully close the butterfly valve.

When the butterfly valve is mounted in the pipe line, the piping boltsare screwed into the lugs 9 with both sides of the valve housing 1 heldby the pipe flanges. The lugs 9 are formed with female screws forengaging the piping bolts and, therefore, the butterfly valve can beused even if it is connected to the pipe at only one side thereof, i.e.it is arranged at an end of the pipe line.

When the operating unit is replaced, the pitch circle diameter of theconnecting bolts 17 can be changed to the corresponding pitch circlediameter by moving the connecting bolts 17 in the radial direction ofthe top flange within the length of the cutouts 12. Also, the width ofthe cutout 12 (i.e. the size of the cutout 12 in the directionperpendicular to the length thereof) is set to such a size that the headof the connecting bolt 17 for connecting the operating unit to the topflange 2 is in contact with and supports the lower end of the top flange2. Thus, the connecting bolts 17 of various sizes can be used within thewidth of the cutouts 12.

In the connecting process, the stem 3 projecting from the centralportion of the top flange 2 is fitted in the fitting portion of theoperating unit. The operating unit is formed with bolt holes in whichthe connecting bolts 17 are inserted. The connecting bolts 17 areinserted into the corresponding cutouts 12 from the outer peripheraledge of the top flange 2 and, after the position of each connecting bolt17 is adjustably changed to a position corresponding to the position ofthe corresponding bolt hole of the operating unit, the connecting bolts17 are inserted into the corresponding bolt holes. After insertion, theconnecting bolts 17 are fastened to connect the operating unit to thetop flange 2.

In this way, the connecting bolts 17 can be moved in a radial directionof the top flange 2 within the length of the cutouts 12 in accordancewith the pitch circle diameter of the operating unit, and the size ofthe connecting bolts 17 can be changed within the width of the cutouts12. Further, the cutouts 12 open outward at the outer peripheral edge ofthe top flange 2, and the connecting bolts 17 can be inserted into thebolt holes of the operating unit from the outer peripheral edge of thetop flange 2. Therefore, even if the valve housing 1 is held by the pipeflanges and the replacement space available for replacing the operatingunit is limited, the connecting bolts 17 can be easily removed and theoperating unit can be replaced by any arbitrary type of operating unit,for example, a manual type or an automatic type, in accordance with theintended application.

FIG. 3 is a front view of the butterfly valve shown in FIG. 2 having agear-type operating unit 16 mounted thereon. When the gear-typeoperating unit 16 is mounted on the butterfly valve, thereduced-diameter stem portion 20 projecting from the top flange 2 isinserted into the fitting portion of the gear-type operating unit 16 sothat the positions of the bolt holes of the gear-type operating unit 16are aligned the positions of the cutouts 12, and the connecting bolts 17are then inserted into the cutouts 12 of the top flange 2 to engage theconnecting bolts 17 in the bolt holes of the gear-type operating unit16.

FIG. 4 is a front view of the butterfly valve shown in FIG. 2 having anautomatic operating unit 18 mounted thereon. This embodiment isdifferent from the embodiment shown in FIG. 3 in that the automaticoperating unit 18 is mounted on the butterfly valve instead of thegear-type operating unit 16. The cutouts 12 of the top flange 2 make itpossible to fix the automatic operating unit 18 on the top flange 2 bythe connecting bolts 17 even if the pitch circle radius of the boltholes of the automatic operating unit 18 is different from that of thegear-type operating unit 16. As the other points are the same as in thecase shown in FIG. 3, a description thereof will be omitted.

As explained above, in the butterfly valve fabricated in accordance withthe present invention, the top flange formed with the cutouts formounting the operating unit is formed integrally with the valve housing,resulting in beneficial effects as described below.

(1) Actuators or gear-type operating units of different mounting sizescan be mounted on the same valve housing, and a compact product can befabricated at low cost without using any additional parts such as thespacer or the joint used in the prior art. Further, the possibilities ofeither an off-center arrangement between the operating unit and the stemor a fitting failure between the joint, the operating unit and the stem,due to the use of the joint, can be eliminated.

(2) As the connecting bolts for fixing the top flange and the operatingunit to each other can be easily removed with the butterfly valveconnected to the pipe line, the operating unit can be mounted ordemounted without removing the butterfly valve from the pipe line, andthe butterfly valve can be freely and easily switched from manual toautomatic mode or from automatic to manual mode in accordance with theintended application. Further, in view of the fact that the spacer forpreventing the stem from coming off is screwed on the top flange of thevalve housing, the stem can be prevented from coming off when removingthe operating unit and, therefore, the operating unit can be replacedsafely.

(3) The bolts for fixing the operating unit do not interfere with thelugs of the valve housing when the operating unit is mounted ordemounted on or from the top flange. Therefore, the body neck and thestem can be designed to be smaller, thereby making a low-cost productionpossible. Also, the shorter body neck and stem and the stronger valvehousing suppresses the deformation of the valve housing, therebyalleviating the problem of a deteriorated sealing performance or anincreased torque in the valve on-off operation. Further, the use of theelliptical seat ring prevents the operating torque from increasing, andmakes it difficult for leakage to occur from the valve seat near thestem through-holes. Also, the possibility of the leakage from the valveseat in the direction perpendicular to the stem axis and the internalleakage from the stem through-holes can be reduced, resulting in thebeneficial effect that the valve can be used in a stable state for along time even if the valve is used so that only one side thereof isconnected to the pipe.

Although the several embodiments of the present invention shown in theaccompanying drawings have been described above, these embodiments areonly illustrative but not limitative. The scope of the present inventionis defined by the appended claims and, therefore, the embodimentsdescribed above can be changed or modified without departing from thescope of the claims.

1. A butterfly valve comprising a integrally formed valve housing havinga substantially cylindrical flow passage formed therein, a disc-shapedvalve element arranged in said flow passage so as to be rotatabletherein, a stem extending from said valve element to the outside of saidvalve housing and supported by said valve housing so as to be rotatable,and an operating unit for rotating said stem, said butterfly valveadapted so that said flow passage is opened and closed by rotating saidstem to thereby rotate said valve element in said flow passage, whereinsaid butterfly valve further comprises a top flange for mounting saidoperating unit thereon by connecting bolts, which is formed integrallywith said valve housing, said top flange formed with a plurality ofcutouts extending from the outer peripheral edge of said top flangetoward the center thereof so that said connecting bolts can be moved insaid plurality of cutouts in a radial direction of said top flange. 2.The butterfly valve according to claim 1, further comprising an annularseat ring extending in a circumferential direction of said flow passageand fitted between the inner peripheral surface of said flow passage andthe outer peripheral edge of said valve element, wherein said stemextends through said seat ring, said seat ring including a body andflanges formed at both axial ends of the body, said seat ring formed sothat the outer periphery of said body thereof has an elliptical shapehaving a long axis extending along an axis of said stem and so that theinner periphery of the body thereof has a circular shape.
 3. Thebutterfly valve according to claim 1, wherein a groove for a spacer forpreventing said stem from coming off to be fitted therein is formed onthe upper surface of said top flange.
 4. The butterfly valve accordingto claim 2, wherein a groove for a spacer for preventing said stem fromcoming off to be fitted therein is formed on the upper surface of saidtop flange.
 5. The butterfly valve according to claim 1, wherein saiddrive operating mounted on said top flange comprises a manual operatingunit.
 6. The butterfly valve according to claim 5, wherein said manualoperating unit comprises a lever-type operating unit or a gear-typeoperating unit.
 7. The butterfly valve according to claim 1, whereinsaid operating unit mounted on said top flange comprises an automaticoperating unit using an actuator.